Sofa



FIG. 1 is a front perspective view of a sofa showing my design;

FIG. 2 is an end perspective view of the sofa, the other end not being disclosed since it is a mirror image of the end shown.

FIG. 3 is a rear perspective view thereof; and

FIG. 4 is a top view thereof. 

The ornamental design for a sofa, as shown and described. 